Arrays of vertically stacked tiers of non-volatile cross point memory cells, methods of forming arrays of vertically stacked tiers of non-volatile cross point memory cells, and methods of reading a data value stored by an array of vertically stacked tiers of non-volatile cross point memory cells

ABSTRACT

An array of vertically stacked tiers of non-volatile cross point memory cells includes a plurality of horizontally oriented word lines within individual tiers of memory cells. A plurality of horizontally oriented global bit lines having local vertical bit line extensions extend through multiple of the tiers. Individual of the memory cells comprise multi-resistive state material received between one of the horizontally oriented word lines and one of the local vertical bit line extensions where such cross, with such ones comprising opposing conductive electrodes of individual memory cells where such cross. A plurality of bit line select circuits individually electrically and physically connects to individual of the local vertical bit line extensions and are configured to supply a voltage potential to an individual of the global horizontal bit lines. Other embodiments and aspects are disclosed.

RELATED PATENT DATA

This patent resulted from a divisional application of U.S. patentapplication Ser. No. 12/765,606, filed Apr. 22, 2010, entitled “ArraysOf Vertically Stacked Tiers Of Non-Volatile Cross Point Memory Cells,Methods Of Forming Arrays Of Vertically Stacked Tiers Of Non-VolatileCross Point Memory Cells, And Methods Of Reading A Data Value Stored ByAn Array Of Vertically Stacked Tiers Of Non-Volatile Cross Point MemoryCells”, naming Sanh D. Tang and Gurtej S. Sandhu as inventors, thedisclosure of which is incorporated by reference.

TECHNICAL FIELD

Embodiments disclosed herein pertain to arrays of vertically stackedtiers of non-volatile cross point memory cells, to methods of formingarrays of vertically stacked tiers of non-volatile cross point memorycells, and to methods of reading a data value stored by an array ofvertically stacked tiers of non-volatile cross point memory cells.

BACKGROUND

Memory is one type of integrated circuitry and is used in computersystems for storing data. Memory is typically fabricated in one or morearrays of individual memory cells. The memory cells might be volatile,semi-volatile, or non-volatile. Non-volatile memory cells can store datafor extended periods of time, and in many instances including when thecomputer is turned off. Volatile memory dissipates and thereforerequires being refreshed/rewritten, and in many instances multiple timesper second. Regardless, the smallest unit in each array is termed as amemory cell and is configured to retain or store memory in an least twodifferent selectable states. In a binary system, the storage conditionsare considered as either a “0” or a “1”. Further, some individual memorycells can be configured to store more than two bits of information.

Integrated circuitry fabrication continues to strive to produce smallerand denser integrated circuits. Accordingly, the fewer components anindividual circuit device has, the smaller the construction of thefinished circuit can be. Likely the smallest and simplest memory cell iscomprised of two conductive electrodes having a programmable materialreceived there-between. Example materials include metal oxides which mayor may not be homogenous, and may or may not contain other materialstherewith. Regardless, the collective material received between the twoelectrodes is selected or designed to be configured in a selected one ofat least two different resistive states to enable storing of informationby an individual memory cell. When configured in one extreme of theresistive states, the material may have a high resistance to electricalcurrent. In contrast in the other extreme, when configured in anotherresistive state, the material may have a low resistance to electricalcurrent. Existing and yet-to-be developed memory cells might also beconfigured to have one or more additional possible stable resistivestates in between a highest and a lowest resistance state. Regardless,the resistive state in which the programmable material is configured maybe changed using electrical signals. For example, if the material is ina high-resistance state, the material may be configured to be in a lowresistance state by applying a suitable voltage across the material.

The programmed resistive state is designed to be persistent innon-volatile memory. For example, once configured in a resistive state,the material stays in such resistive state even if neither a current nora voltage is applied to the material. Further, the configuration of thematerial may be repeatedly changed from one resistance state to anotherfor programming the memory cell into different of at least two resistivestates. Upon such programming, the resistive state of the material canbe determined by appropriate signals applied to one or both of the twoelectrodes between which the material is received.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagrammatic top plan view of a substrate in accordance withan embodiment of the invention.

FIG. 2 is a diagrammatic schematic of an array of vertically stackedtiers of non-volatile cross point memory cells in accordance with FIG. 1and an embodiment of the invention.

FIG. 3 is an alternate embodiment to that depicted by FIG. 2.

FIG. 4 is a diagrammatic top plan view of another substrate inaccordance with an embodiment of the invention.

FIG. 5 is diagrammatic schematic of an array of vertically stacked tiersof non-volatile cross point memory cells in accordance with FIG. 4 andan embodiment of the invention.

FIG. 6 is an alternate embodiment to that depicted by FIG. 5.

FIG. 7 is another alternate embodiment to that depicted by FIG. 5.

FIG. 8 is diagrammatic perspective view of portions of circuitryencompassing the embodiment of FIG. 5.

FIG. 9 is diagrammatic perspective view of portions of circuitry of theembodiment of FIGS. 1 and 2.

FIG. 10 is a diagrammatic perspective view of a semiconductor substratefragment in process in accordance with an embodiment of the invention.

FIG. 11 is a view of the FIG. 10 substrate at a processing stepsubsequent to that shown by FIG. 10.

FIG. 12 is a view of the FIG. 11 substrate at a processing stepsubsequent to that shown by FIG. 11.

FIG. 13 is a view of the FIG. 12 substrate at a processing stepsubsequent to that shown by FIG. 12.

FIG. 14 is a view of the FIG. 13 substrate at a processing stepsubsequent to that shown by FIG. 13.

FIG. 15 is a view of the FIG. 14 substrate at a processing stepsubsequent to that shown by FIG. 14.

FIG. 16 is a view of the FIG. 15 substrate at a processing stepsubsequent to that shown by FIG. 15.

FIG. 17 is a view of the FIG. 16 substrate at a processing stepsubsequent to that shown by FIG. 16.

FIG. 18 is a view of the FIG. 17 substrate at a processing stepsubsequent to that shown by FIG. 17.

FIG. 19 is a view of the FIG. 18 substrate at a processing stepsubsequent to that shown by FIG. 18.

FIG. 20 is a view of the FIG. 19 substrate at a processing stepsubsequent to that shown by FIG. 19.

FIG. 21 is a view of the FIG. 20 substrate at a processing stepsubsequent to that shown by FIG. 20.

FIG. 22 is a view of the FIG. 21 substrate at a processing stepsubsequent to that shown by FIG. 21.

FIG. 23 is a view of the FIG. 22 substrate at a processing stepsubsequent to that shown by FIG. 22.

FIG. 24 is a view of the FIG. 23 substrate at a processing stepsubsequent to that shown by FIG. 23.

FIG. 25 is a view of the FIG. 24 substrate at a processing stepsubsequent to that shown by FIG. 24.

FIG. 26 is a view of the FIG. 25 substrate at a processing stepsubsequent to that shown by FIG. 25.

FIG. 27 is a view of the FIG. 26 substrate at a processing stepsubsequent to that shown by FIG. 26.

FIG. 28 is a view of the FIG. 27 substrate at a processing stepsubsequent to that shown by FIG. 27.

FIG. 29 is a view of the FIG. 28 substrate at a processing stepsubsequent to that shown by FIG. 28.

FIG. 30 is a view of the FIG. 29 substrate at a processing stepsubsequent to that shown by FIG. 29.

FIG. 31 is a view of the FIG. 30 substrate at a processing stepsubsequent to that shown by FIG. 30.

FIG. 32 is a view of the FIG. 31 substrate at a processing stepsubsequent to that shown by FIG. 31.

FIG. 33 is a diagrammatic perspective view of a semiconductor substratefragment in process in accordance with an embodiment of the invention.

FIG. 34 is a view of the FIG. 33 substrate at a processing stepsubsequent to that shown by FIG. 33.

FIG. 35 is a view of the FIG. 34 substrate at a processing stepsubsequent to that shown by FIG. 34.

FIG. 36 is a view of the FIG. 35 substrate at a processing stepsubsequent to that shown by FIG. 35.

FIG. 37 is a diagrammatic perspective view of a semiconductor substratefragment in process in accordance with an embodiment of the invention.

FIG. 38 is a view of the FIG. 37 substrate at a processing stepsubsequent to that shown by FIG. 37.

FIG. 39 is a diagrammatic perspective view of a semiconductor substratefragment in process in accordance with an embodiment of the invention.

FIG. 40 is a view of the FIG. 39 substrate at a processing stepsubsequent to that shown by FIG. 39.

FIG. 41 is a view of the FIG. 40 substrate at a processing stepsubsequent to that shown by FIG. 40.

FIG. 42 is a view of the FIG. 41 substrate at a processing stepsubsequent to that shown by FIG. 41.

FIG. 43 is a view of the FIG. 42 substrate at a processing stepsubsequent to that shown by FIG. 42.

FIG. 44 is a view of the FIG. 43 substrate at a processing stepsubsequent to that shown by FIG. 43.

FIG. 45 is a view of the FIG. 44 substrate at a processing stepsubsequent to that shown by FIG. 44.

FIG. 46 is a diagrammatic view of a computer embodiment.

FIG. 47 is a block diagram showing particular features of themotherboard of the FIG. 46 computer embodiment.

FIG. 48 is a high level block diagram of an electronic systemembodiment.

FIG. 49 is a simplified block diagram of a memory device embodiment.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS

Embodiments of the invention encompass arrays of vertically stackedtiers of non-volatile cross point memory cells. Initial example sucharrays are described with reference to FIGS. 1-7. Referring initially toFIGS. 1 and 2, an example array 10 is fabricated relative to a substrate12. In one embodiment, substrate 12 comprises a semiconductor substrate.In the context of this document, the term “semiconductor substrate” or“semiconductive substrate” is defined to mean any constructioncomprising semiconductive material, including, but not limited to, bulksemiconductive materials such as a semiconductive wafer (either alone orin assemblies comprising other materials thereon), and semiconductivematerial layers (either alone or in assemblies comprising othermaterials). The term “substrate” refers to any supporting structure,including, but not limited to, the semiconductive substrates describedabove. Substrate 12 may be considered as having a primary elevationallyoutermost surface which can be considered to define a horizontaldirection or orientation, with the direction orthogonal thereto defininga vertical direction or orientation. Such outermost surface may or maynot be planar.

Memory cells of the array are fabricated within an array area 14 (FIG.1). Logic circuitry would typically be fabricated outside of array area14. Control and/or other peripheral circuitry for operating the memoryarray may or may not wholly or partially be received within array area14, with such array area as a minimum encompassing all of the memorycells of a given array/sub-array. Further, multiple sub-arrays mightalso be fabricated and operated independently, in tandem, or otherwiserelative one another. As used in this document, a “sub-array” may alsobe considered as an array.

Array 10 includes a plurality of tiers 18, 20, 22 of memory cells 34,with individual of the tiers comprising a plurality of horizontallyoriented word lines 24. For simplicity of illustration, FIG. 2 depictsthree tiers, although only two tiers or more than three tiers may befabricated. Array 10 includes a plurality of bit lines 26 thatindividually comprise horizontally oriented global bit lines 28 havinglocal vertical bit line extensions 30 extending therefrom throughmultiple of the tiers of memory cells. FIGS. 1 and 2 diagrammaticallyshow only a few of such word lines and bit lines for clarity, with array10 likely including thousands or millions of such. Further only threememory cells 34 are shown associated with the individual word linesegments in FIG. 2, with the number of such likely being in thethousands or millions along a word line. Word lines 24 and global bitlines 28 may run perpendicular relative to one another (as shown inFIGS. 1 and 2), at one or more angles other than perpendicular relativeto one another (not shown in FIGS. 1 and 2), or parallel relative oneanother (not shown in FIGS. 1 and 2). Further, global bit lines 28 neednot be straight or run parallel relative to one another, nor do wordlines 24 need to be straight or run parallel relative to one another.Further, bit lines 26 may include other extensions (not shown) beyondlocal vertical bit line extensions 30, and word lines 24 may compriseextensions (not shown).

Memory cells 34 individually comprise multi-resistive state material 33which is received between one of the word lines 24 and one of the localvertical bit line extensions 30 where such cross with such comprisingopposing conductive electrodes of an individual memory cell. Individualmemory cells may encompass other devices, for example a diode, but willas a minimum comprise multi-resistive state material received betweenindividual crossings of the word lines and local vertical bit lineextensions. Example materials and example details of construction willbe described subsequently.

In one embodiment, a plurality of bit line select circuits 38individually electrically and physically connect to individual of localvertical bit line extensions 30 and are configured to supply a voltagepotential to an individual of global horizontal bit lines 28. In oneembodiment, a plurality of bit line select circuits 38 individuallyelectrically and physically connect to individual of local vertical bitline extensions 30 and are configured to supply a voltage potential tomultiple of local vertical bit line extensions 30. Bit line selectcircuits 38 may be as simple as a single electronic device, for examplethe depicted field effect transistor 40, or may encompass multipleelectronic devices. Bit line select circuits 38 may be receivedpartially or wholly within array area 14, or partially or wholly outsideof array area 14.

In one embodiment, individual bit line select circuits 38 are configuredto supply a voltage potential to multiple of local vertical bit lineextensions 30 through individual of the global horizontal bit lines fromwhich the individual local vertical bit line extension 30 extends. Forexample, conductive lines 42 are shown electrically connecting with bitline select circuits 38. Such may be received partially or wholly withinarray area 14, or partially or wholly outwardly thereof. Regardless,such may be provided at a selected voltage potential with bit lineselect circuit 38 operated to supply a voltage potential to the localvertical bit line extension 30 to which such connects. Such voltagepotential is supplied to multiple other of the local vertical bit lineextensions 30 connected to the same global bit line 28 through suchglobal bit line. In one embodiment, and as shown, individual global bitlines 28 have only a single bit line select circuit 38 that electricallyconnects thereto through only a single vertical bit line extension 30.Alternately, individual of the global bit lines may have more than one(not shown) bit line select circuit 38 connected therethrough throughmultiple vertical bit line extensions 30.

A plurality of row decode select circuits 39 individually electricallyconnect with individual of word lines 24. Alternate configurations arecontemplated. Regardless, row decode select circuits 39 may comprise oneor more individual electronic components/devices.

In one embodiment, individual of local vertical bit lines 30 have twoopposing longitudinal ends 43, 44 one of which (end 43) electrically andphysically connects with one of horizontal global bit lines 28. In oneembodiment, individual of bit line select circuits 38 physically connectwith the other end (end 44) of two longitudinal ends 43, 44 ofindividual of local vertical bit line extensions 30. Regardless, in oneembodiment, at least one of tiers 18, 20, 22 of memory cells 34 isreceived elevationally between individual of the global horizontal bitlines 28 and the physical connection of individual of the bit lineselect circuits 38 with individual of local vertical bit line extensions30. In one embodiment, and as shown, all tiers 18, 20, 22 of memorycells 34 are received elevationally between individual of globalhorizontal bit lines 28 and physical connection of individual of the bitline select circuits 38 with individual local vertical bit lineextensions 30. Regardless, FIG. 2 depicts one example embodiment whereinthe global horizontal bit lines 28 are received elevationally outward oftiers 18, 20, 22 of memory cells 34. FIG. 3 depicts an alternate exampleembodiment array 10 a wherein global horizontal bit lines 28 arereceived elevationally inward of tiers 18, 20, 22 of memory cells 34.

Another embodiment array 10 b of vertically stacked tiers ofnon-volatile cross point memory cells is described with reference toFIGS. 4 and 5. Like numerals from the above-described embodiments havebeen used where appropriate, with differences being indicated with thesuffix “b” or with different numerals. In array 10 b, horizontallyoriented word lines 24 b within individual tiers 18, 20, 22 compriseglobal horizontal word lines 25 having local horizontal word lineextensions 27. The local horizontal word line extensions respectivelyextend from the global horizontal word lines at an angle (not at 180°),and in one embodiment as shown may extend orthogonally from the globalhorizontal word lines. In one embodiment, the individual of tiers 18, 20and 22 comprise two global horizontally oriented word lines 25individually adjacent opposite sides of the array and from which localhorizontal word line extensions 27 extend. In one embodiment and asshown, local horizontal word line extensions 27 extend from one of thetwo global horizontal word lines 25 across the array within anindividual tier toward the other of two global word lines 25 in theindividual tier. In one embodiment and as shown, local horizontal wordline extensions 27 extending from the two global word lines 25 alternatewith the local horizontal word line extensions 27 extending from theother of two global word lines 25 within an individual of the tiers.Regardless, in one embodiment, individual of tiers 18, 20, 22 contain nomore than two global word lines. By way of example, FIG. 4 depicts twohorizontal global word lines 25 which are individually adjacent oppositesides of array 10 b within array area 14 b. Thousands or millions ofmemory cells 34 would likely be associated with each local horizontalword line extension 27.

In one embodiment and as shown, array 10 b has two, and only two, rowdecode select circuits 39 within an individual of tiers 18, 20, 22.Regardless, in one embodiment, array 10 b comprises a plurality of localvertical bit line extension select circuits 45 individually,electrically, and physically connected between an individual of globalhorizontal bit lines 28 b and an individual of local vertical bit lineextensions 30 b connected therewith. Such may be encompassed by one ormore electronic devices received wholly or partially within array area14 b, or wholly or partially outside of array area 14 b. FIG. 5 depictsbit line extension select circuits 45 as comprising a field effecttransistor 47 having a control gate line 29.

FIGS. 4 and 5 depict an example embodiment wherein global word lines 25run parallel relative to one another within a tier and global bit lines28 b run parallel relative to one another, and also wherein global wordlines 25 run parallel with/relative to global bit lines 28 b. FIG. 6 isintended to depict an alternate embodiment array 10 c wherein globalword lines 25 run perpendicular to global bit lines 28 c. Like numeralsfrom the above-described embodiments have been used where appropriate,with differences being indicated with the suffix “c”.

The embodiments of FIGS. 4-6 depict the global bit lines and associatedlocal vertical bit line extension select circuits 45 receivedelevationally inward of the tiers of memory cells. Alternately, suchcould be received elevationally outward (not shown) of the tiers ofmemory cells, for example analogous to the alternate embodiments ofFIGS. 2 and 3. Further, the embodiments of FIGS. 2 and 3 may incorporateword lines having global horizontally oriented word lines with localhorizontal word line extensions extending there-from, for example inmanners somewhat similar to that described immediately above withrespect to the FIGS. 4-6 embodiments.

An embodiment of the invention encompasses an array of verticallystacked tiers of non-volatile cross point memory cells. Such arraycomprises a plurality of horizontally oriented word lines independent ofwhether an individual tier comprises a plurality of such word lines andindependent of whether any individual of the horizontally oriented wordlines comprises global horizontal word lines having local horizontalword line extensions extending therefrom. Regardless, such arraycomprises a plurality of horizontally oriented global bit lines havinglocal vertical bit line extensions extending through multiple tiers ofmemory cells. Individual of the memory cells comprise multi-resistivestate material received between one of the horizontally oriented wordlines and one of the local vertical bit line extensions where suchcross. Such array includes at least one, and no more than two, rowdecode select circuits for individual of the tiers. By ways of exampleonly, the embodiments of FIGS. 4-6 depict example such circuitry whereintwo and only two row decode select circuits are provided for individualof the tiers. Alternate circuitry comprising two and only two row decodeselect circuits for the individual tiers is also contemplated.

FIG. 7 depicts an alternate embodiment array 10 d which comprises onlyone row decode select circuit for individual of the tiers. Like numeralsfrom the above-described embodiments had been utilized whereappropriate, with differences being indicated with the suffix “d”. Byway of examples only, the embodiments of FIGS. 1-6 may be considered asforming individual memory cells on opposing sides of the local verticalbit line extensions. Array 10 d of FIG. 7 only uses one side ofindividual local vertical bit line extensions in an individual tier, andonly a single row decode select circuit 39 for each tier. Alternateconstructions may be used. Further, FIG. 7 is analogous to the FIG. 5layout, although the FIG. 6 or alternate layouts could of course beused.

An embodiment of the invention encompasses a method of reading a datavalue stored by an array of vertically stacked tiers of non-volatilecross point memory cells, wherein individual of the memory cellscomprise multi-resistive state material received between a word line anda bit line where such cross. Such a method encompasses pulling one of aplurality of horizontally oriented word lines within individual tiers ofmemory cells to a first voltage potential. One of a plurality ofhorizontally oriented global bit lines having local vertical bit lineextensions extending through multiple of the tiers of memory cells iselectrically connected to a voltage source via one of the vertical bitline extensions, thereby pulling the one bit line to a second voltagepotential. Based upon the pulling of the one of the horizontallyoriented word lines to the first voltage potential and the pulling ofthe one of the horizontally oriented global bit lines to the secondvoltage potential, a data value stored by one of the memory cells of thearray is determined.

In one embodiment, the determining of the data value is based on acurrent flowing through the one of the memory cells, with the currentresulting from a difference between the first voltage potential and thesecond voltage potential. In one embodiment, the first voltage potentialis greater than the second voltage potential. In one embodiment, theelectrically connecting to a voltage source is with only one of thelocal vertical bit line extensions. In one embodiment, a bit line selectcircuit is physically connected between the one local vertical bit lineextension and the voltage source, with the stated electricallyconnecting being accomplished at least in part by operation of the bitline select circuit. By ways of example only, any of the embodiments ofthis paragraph and the immediately preceding paragraph may be conductedusing the circuitry embodiments of FIGS. 1-3.

In another embodiment, one of a plurality of vertically oriented localvertical bit line extensions of a plurality of horizontally orientedglobal bit lines is pulled to a first voltage potential. The verticallyoriented bit line extensions extend through individual tiers of memorycells. One of a plurality of horizontally oriented global word lines ispulled to a second voltage potential. The global word lines havehorizontally oriented local word line extensions which cross more thanone of the plurality of vertically oriented bit line extensions. Basedon the pulling of the one of the local vertical bit line extensions tothe first voltage potential and the pulling of the one of the globalword lines to the second voltage potential, a data value stored by oneof the memory cells of the array is determined.

In one embodiment, the one local vertical bit line extension may beconsidered as a first local vertical bit line extension and the one ofthe memory cells may be considered as a first memory cell positionedbetween the local vertical bit line extension and one of the localhorizontal word line extensions. While the first local vertical bit lineextension is being pulled to the first voltage potential and the one ofthe horizontally oriented global word lines is being pulled to thesecond voltage potential, a second one of the local vertical bit lineextensions is pulled to the first voltage potential. Based on thepulling of the second one of the local vertical bit line extensions tothe first voltage potential and the pulling of the one of the global bitlines to the second voltage potential, a data value stored by the secondone of the memory cells positioned between the second local vertical bitline extension and the one local horizontal word line extension isdetermined.

In one embodiment, the local word line extensions run parallel relativeto one another. In one embodiment, the second voltage potential isgreater than the first voltage potential. In one embodiment, thedetermining of the data value is based on a current flowing through theone of the memory cells. By ways of example only, any of the embodimentsof this paragraph and the immediately preceding two paragraphs may beconducted using the circuitry embodiments of FIGS. 4-7.

As used herein, pulling a conductive node to a voltage potential refersto causing the conductive node to be at or very close to the voltagepotential. The voltage potential may be positive or negative and mayhave substantially any magnitude. For example, the voltage potential maybe ground. In pulling a conductive node to a voltage potential, it is tobe understood that individual voltage potentials measured at variouslocations of the conductive node might not be exactly the same due to,for example, the resistance of the conductive node itself. However, theindividual voltage potentials may be substantially the same since theindividual voltage potentials may be as close to the voltage potentialas the physical limitations of the conductive node will allow. In someinstances, the conductive node may be connected directly to a voltagesource having the voltage potential. For example, a bit line (includingany extensions of the bit line) may be pulled to ground by connectingthe bit line (and/or one or more of any extensions of the bit line) toground, or a word line (including any extensions of the word line) maybe pulled to 3.5 volts by connecting the word line (and/or one or moreof any extensions of the word line) to a voltage source of 3.5 volts.Additionally or alternatively, the conductive node may be pulled to avoltage potential by circuitry intermediate the conductive node and avoltage source, such as a sense amplifier.

FIG. 8 diagrammatically depicts a portion of an example substrate 50comprising components in accordance with the FIG. 6 schematic. Such ishighly diagrammatic and only shows a broken portion of a single tier 20for clarity in the drawings. Field effect transistors 47 of localvertical bit line extension select circuits 45 are shown as respectivevertically oriented transistors having a wrap-around control gate line29. Field effect transistors 47 respectively have an example source 37,a channel 39, and a drain 41, with local vertical bit line extensions 30b electrically connecting with individual of drains 41. Only a singlerow of local vertical bit line extensions 30 b is shown in FIG. 8 forclarity. Global horizontal bit lines 28 c electrically connect withsources 37 of individual field effect transistors 47, with the structureas shown being elevationally supported over an example insulativedielectric 43. Other layers of circuitry components may of course befabricated below or within dielectric 43, as well as circuit componentsfabricated above the depicted upper ends of local vertical bit lineextensions 30 b.

FIG. 9 diagrammatically shows a portion of an alternate embodimentsubstrate 50 a fabricated in accordance with the FIGS. 1 and 2schematic. Like numerals from the FIG. 8 embodiment have been used whereappropriate, with differences being indicated with the suffix “a”. Noneof tiers 18, 20, 22 is shown, with only a single bit line 28 and asingle local vertical bit line extension 30 being shown for clarity.Field effect transistor 40 of bit line select circuit 38 includes asource 37 a, a channel 39 a, and a drain 41 a. A wrap-around gateconstruction (not shown) may be used proximate channel region 39 aanalogous to the gate structure 29 of FIG. 8.

Example constructions of arrays of vertically stacked tiers ofnon-volatile cross point memory cells and methods of fabricating suchare next described with reference to FIGS. 10-32. Like numerals from theabove-described embodiments have been used where appropriate. Referringto FIG. 10, an example construction 54 includes an elevationally innerdielectric 56 having alternating rows of different composition materials57, 58 formed thereover. In one embodiment, material 58 is insulative.Example materials 56 and 58 include doped or undoped silicon dioxide,and an example material 57 comprises silicon nitride. In one embodiment,material 57 will be wholly or at least mostly sacrificial within thearray. Layers 57 as depicted correspond with tiers 18, 20, and 22 wherememory cells and horizontally oriented word lines will be formed. Anadditional outer tier 16 is used in one embodiment, as will be apparentin the continuing discussion. An additional inner tier (not numericallydesignated) is received between tier 22 and dielectric 56. Fewer or morethan the depicted tiers may be used, and tier 16 is not required in allembodiments. An example thickness range for each of layers 57 and 58 is50 nanometers, with the elevationally outermost insulative layer 58being thicker than the other layers 58, for example of a thickness from65 to 100 nanometers. An etch stop capping layer 60 has been formed overelevationally outermost insulative layer 58, with undoped polysilicondeposited to a thickness of 30 nanometers being an example.

Referring to FIG. 11, horizontally elongated trenches 62 have beenformed within insulative material 58 and through material 57. Such maybe formed initially using a suitable mask (not shown) over material 60to form the depicted trench mask openings 62 in material 60, and thenusing suitable alternating dry anisotropic etching chemistries to etchmaterials 58 and 57. In one embodiment, trenches 62 have a minimumlateral width of F, with the material immediately between adjacent oftrenches 62 having a lateral thickness/width of 3F. Pitch multiplicationmay or may not be used. In one example, the mask used for producing theFIG. 11 pattern might initially be fabricated to provide 2F width ofopenings for each of the trenches and material between immediatelyadjacent trenches, with the trench openings subsequently being reducedin size by a 1F thickness deposition, thereby increasing the width ofthe material between the trenches to 3F.

Referring to FIG. 12, lateral recesses 64 have effectively been formedwithin insulative material 58 within trenches 62. Such may be formed,for example, by isotropic wet etching material 57. For example wherematerial 57 comprises silicon nitride, such may be isotropically etchedhighly selectively relative to an example insulative silicon dioxidematerial 58. Accordingly, lateral recesses 64 may effectively be formedwithin insulative material 58 with little or no etching thereof. In thecontext of this document, a “selective” etch requires removal of onematerial relative to another at a rate of at least 1.5:1. An exampledepth of lateral recess of material 57 relative to the example verticalsidewalls of material 58 of trenches 62 is 25 nanometers.

Referring to FIG. 13, trenches 62 and lateral recesses 64 have beenlined with a first conductive material 66. An example material isplatinum, for example in any one or combinations of elemental, alloy, orcompound forms. An example thickness is from 10 nanometers to 15nanometers and ideally is ineffective to fill or pinch-off between thetiers.

Referring to FIG. 14, lined trenches 62 and lined lateral recesses 64have been filled with a second conductive material 68 which is differentin composition from that of first conductive material 66. An examplesecond conductive material is conductively doped polysilicon, althoughother metal or nonmetal-containing conductive materials may be used.

Referring to FIG. 15, second conductive material 68 has been etchedwithin trenches 62 selectively relative to first conductive material 66to leave second conductive material 68 within, at least, lined lateralrecesses 64. In one embodiment, such etching is conducted to beanisotropic, for example as shown.

Referring to FIG. 16, first conductive material 66 has been etchedselectively relative to second conductive material 68 to remove firstconductive material 66 from being received over sidewalls of trenches 62defined by material 58 between the tiers. Thereby, in one embodiment, aplurality of horizontally oriented word lines 24 are formed withinindividual of tiers 16, 18, 20 and 22 which comprise first conductivematerial 66 and second conductive material 68. The depicted word lineswhich are formed may or may not comprise either of a global horizontalword line and/or a local horizontal word line extension extending from aglobal horizontal word line. In one embodiment, the etching of firstconductive material 66 is conducted isotropically, and in one example isconducted wet. For example, with respect to a predominantlyplatinum-comprising first conductive material 66, a suitable isotropicetching chemistry to produce the FIG. 16 construction comprises anaqueous etching solution comprising HNO₃ and HCl. Lateral recessing, asshown, may occur of first conductive material 66 relative to sidewallsof trenches 62 and, if so, may increase word line resistance due toreduction of the higher conductive platinum versus the exampleconductively doped polysilicon material 68 in an example finished wordline construction. Regardless, the etching of first conductive material66 may also etch second conductive material 68 laterally to some degree.

The above description with respect to FIGS. 10-16 is but one exampleembodiment of forming multiple tiers that individually comprise aplurality of horizontally oriented word lines. In one embodiment, anelevationally outermost tier 16 of tiers 16, 18, 20 and 22 will comprisedummy horizontally oriented word lines 24 that are non-functional withinthe array in a finished circuitry construction. In one embodiment, thedummy word lines are taller than the word lines of an immediately nextelevationally inner of the tiers, and in one embodiment taller than allelevationally inner of the word lines.

Regardless, in one embodiment, word lines 24 are of a conductivelyfilled C-shape in a vertical cross section. An outline of the C-shapecomprises one conductive material 66, with a central portion of theC-shape being filled with another conductive material 68 of differentcomposition from the one conductive material 66. Materials 66 and 68 mayor may not, respectively, be homogenous. Regardless, in one embodiment,conductive material 66 is of higher conductivity than conductivematerial 68. In one embodiment and as shown, the etching of firstconductive material 66 laterally recesses first conductive material 66relative to sidewalls of second conductive material 68 which is withinthe central portion of the C-shape outline defined by first material 66.In one embodiment and as shown, second conductive material 68 extendslaterally outward of the C-shape outline defined by first material 66.

Referring to FIG. 17, trenches 62 in one embodiment have been overfilledwith a material 70, for example silicon dioxide, which has then beenrecessed back by etching to have an elevationally outermost surfacereceived within the elevational confines of dummy tier 16. In oneembodiment, such is conducted selectively relative to etch stop layer60. In FIG. 17 and subsequent figures, various materials are not shownin the right-most portion of the view for clarity in the construction.For example, material 60, top tier 16 and material 58 are not shown inthe right-most portion.

Referring to FIG. 18, a material 72, for example the same as that ofetch stop layer 60 (not shown), has been deposited to overfill remainingvolume of trenches 62. Subsequently, materials 72 and 60 have beenplanarized back at least to the elevationally outermost surface ofoutermost material 58.

Referring to FIG. 19, another etch stop layer 74, for example of thesame composition as that of material 72 (i.e., polysilicon), has beendeposited. An example thickness is 30 nanometers.

Referring to FIG. 20, a trench mask pattern (not shown) has been used toetch the depicted longitudinally elongated trenches through materials 74and 58. The material 74 and 58 between such longitudinal trenches iseffectively used as a mask to etch openings 76 into materials 57 and 58there-below selectively relative to horizontally oriented word lines 24.Etching chemistry may be altered to etch materials 57 and 58 selectivelyrelative to each other and other exposed materials to extend openings 76down to dielectric 56. In one embodiment, openings 76 are so etchedusing dummy horizontally oriented word lines 24 within elevationallyoutermost tier 16 as a hardmask to horizontally oriented word linesreceived elevationally inward thereof. In one embodiment, the dummy wordlines 24 within tier 16 comprise elevationally outermost surfacescomprising platinum which may function as a good hard-masking materialin conducting conventional dry anisotropic selective etches inseparately etching silicon dioxide and silicon nitride. Regardless,blocks of material 57 are formed within the array.

Referring to FIG. 21, insulative material 80 has been deposited tooverfill the depicted trenches and openings, and planarized back atleast to elevationally outermost surfaces of material 74. Material 80may or may not be the same composition as material 58, Material 80 wouldalso fill the depicted right-illustrated portion of FIG. 21 but, again,is not shown for clarity. Such provides but one example embodiment ofeffectively encapsulating spaced sacrificial blocks 78 within insulativematerial, for example insulative materials 80 and 58.

Referring to FIG. 22, the hard-masking has been inverted by recessingoxide material 80 selectively relative to polysilicon material 74 (notshown), followed by deposition of polysilicon, followed by polysiliconplanarization at least to the elevationally outermost surfaces ofmaterial 58.

Referring to FIG. 23, another etch stop layer 84, for example of thesame composition of material 82 (i.e., polysilicon), has been depositedto an example thickness of 30 nanometers. With materials 84, 82, 72 and68 used as etch stopping/hardmask materials, a mask (not shown) has beenused to etch openings 86 into materials 58 and 80. In one embodiment,such etching of openings 86 is conducted anisotropically. Regardless, inone embodiment, the processing depicted through FIG. 23 is but oneexample of forming of a plurality of sacrificial spaced blocks 78adjacent horizontal word lines 24. Sacrificial blocks 78 may comprise,consist of, or consist essentially of any one or combination ofinsulative, conductive, or semiconductive materials. In one embodimentand as shown, spaced sacrificial blocks 78 may be formed to compriserectangular faces.

Referring to FIG. 24, exposed spaced sacrificial blocks 78 (not shown)have been selectively etched relative to materials 80 and 58, therebyleaving void spaces 88 there-behind. In one example embodiment, suchetching is conducted isotropically, and in one example embodiment isconducted wet. An example wet etching chemistry that will isotropicallywet etch a silicon nitride 57 selectively relative to silicon dioxide 58and 80, and platinum 66, includes a heated aqueous solution of H₃PO₄.

Referring to FIG. 25, and in but one embodiment, void spaces 88 (notshown) have been filled with multi-resistive state material 33, withprogrammable spaced blocks 90 effectively being formed there-from. Anexample technique for doing so includes deposition of one or moresuitable multi-resistive state materials to within openings 86 tooverfill such openings, followed by anisotropic etching of such materialfrom within openings 86 such that the multi-resistive state material 33remains filling the previous void spaces. In one embodiment, theprogrammable spaced blocks 90 are formed to comprise rectangular faces.Multi-resistive state material 33 may be homogenous or non-homogenous,and may comprise one or more different compositions and/or layers.Accordingly, material 33 might be deposited/formed in more than onestep.

In one embodiment, a method of forming an array of vertically stackedtiers of non-volatile cross point memory cells includes exchangingsacrificial spaced blocks with programmable spaced blocks comprisingmulti-resistive state material. Such may comprise etching of thesacrificial spaced blocks followed by filling void space leftthere-behind with multi-resistive state material. The above processingwith respect to FIGS. 10-25 comprises but one example such technique.Another embodiment is described below wherein the void spaces which arecreated are lined with multi-resistive state material.

By ways of example only, material 33 might comprise multi-resistivestate metal oxide-comprising material, further for example comprisingtwo different layers or regions generally regarded as or understood tobe active or passive regions, although not necessarily. Example activecell region compositions which comprise metal oxide and can beconfigured in multi-resistive states include one or a combination ofSr_(x)Ru_(y)O_(z), Ru_(x)O_(y), and In_(x)Sn_(y)O_(z). Other examplesinclude MgO, Ta₂O₅, SrTiO₃, ZrO_(x) (perhaps doped with La), and CaMnO₃(doped with one or more of Pr, La, Sr, or Sm). Example passive cellregion compositions include one or a combination of Al₂O₃, TiO₂, andHfO₂. Regardless, material 33 might comprise additional metal oxide orother materials not comprising metal oxide. Example materials andconstructions for a multi-resistive state region comprising one or morelayers including a programmable metal oxide-comprising material aredescribed and disclosed in U.S. Pat. Nos. 6,753,561; 7,149,108;7,067,862; and 7,187,201, as well as in U.S. Patent ApplicationPublication Nos. 2006/0171200 and 2007/0173019. Further as isconventional, multi-resistive state metal oxide-comprising materialsencompass filament-type metal oxides, ferroelectric metal oxides andothers, and whether existing or yet-to-be developed, as long asresistance of the metal oxide-comprising material can be selectivelychanged.

Multi-resistive state material 33 may comprise memristive material. Inone embodiment, multi-resistive state material 33 may be staticallyprogrammable semiconductive material which comprises mobile dopants thatare received within a dielectric such that the material is staticallyprogrammable between at least two different resistance states. At leastone of the states includes localization or gathering of the mobiledopants such that a dielectric region is formed within material 33, andthereby provides a higher resistance state. Further, more than twoprogrammable resistance states may be used. In the context of thisdocument, a “mobile dopant” is a component (other than a free electron)of the semiconductive material that is movable to different locationswithin said dielectric during normal device operation of repeatedlyprogramming the device between at least two different static states byapplication of voltage differential to the pair of electrodes. Examplesinclude atom vacancies in an otherwise stoichiometric material, and atominterstitials. Specific example mobile dopants include oxygen atomvacancies in amorphous or crystalline oxides or other oxygen-containingmaterial, nitrogen atom vacancies in amorphous or crystalline nitridesor other nitrogen-containing material, fluorine atom vacancies inamorphous or crystalline fluorides or other fluorine-containingmaterial, and interstitial metal atoms in amorphous or crystallineoxides. More than one type of mobile dopant may be used. Exampledielectrics in which the mobile dopants are received include suitableoxides, nitrides, and/or fluorides that are capable of localizedelectrical conductivity based upon sufficiently high quantity andconcentration of the mobile dopants. The dielectric within which themobile dopants are received may or may not be homogenous independent ofconsideration of the mobile dopants. Specific example dielectricsinclude TiO₂, AlN, and/or MgF₂.

In one embodiment, a multi-resistive state material 33 that comprisesoxygen vacancies as mobile dopants may comprise a combination of TiO₂and TiO_(2−x) in at least one programmed resistance state depending onlocation of the oxygen vacancies and the quantity of the oxygenvacancies in the locations where such are received. In one embodiment, amulti-resistive state material 33 that comprises nitrogen vacancies asmobile dopants may comprise a combination of AlN and AlN_(1−x) in atleast one programmed state depending on location of the nitrogenvacancies and the quantity of the nitrogen vacancies in the locationswhere such are received. In one embodiment, a multi-resistive statematerial 33 that comprises fluorine vacancies as mobile dopants maycomprise a combination of MgF₂ and MgF_(2−x) in at least one programmedresistance state depending on location of the fluorine vacancies and thequantity of the fluorine vacancies in the locations where such arereceived. In one embodiment, the mobile dopants comprise aluminum atominterstitials in a nitrogen-containing material.

A plurality of horizontally oriented global bit lines are formed whichhave local vertical bit line extensions extending through multiple ofthe tiers. Individual of the local vertical bit line extensions may bereceived laterally adjacent programmable spaced blocks received withinmultiple of the tiers, with the programmable spaced blocks also beingreceived adjacent the horizontally oriented word lines. For example andby way of example only, the openings 86 remaining after the FIG. 25processing may be used to define and/or form local vertical bit lineextensions there-within, and to encompass any of the example circuitriesshown in any of the embodiments of FIGS. 1-6 by way of examples.Accordingly, global horizontal bit lines and/or bit line select circuitsand/or local vertical bit line extension select circuits (none beingshown) may have previously been fabricated elevationally inward of thetier below tier 22. Alternately, one or more of such circuitrycomponents may be fabricated elevationally outward of the example dummytier 16. Alternately, one or more of such circuitry components may befabricated elevationally between (not shown) the tiers.

Regardless, the description proceeds with reference to FIGS. 26-31 ofexample techniques of forming local vertical bit line extensions. Suchmay comprise one or more conductive materials. Further as statedpreviously, the multi-resistive state material in the methods and arraysdisclosed herein may be of a single general composition or of multipledifferent compositions. Referring to FIG. 26, a multi-resistive statematerial 92 has been deposited to line openings 86. Such is simply shownas a thick black line in the drawings for clarity. In one embodiment, anexample multi-resistive state material 33 and 92 is a composite ofPr_(0.7)Ca_(0.3)MnO₃ and a yttrium-zirconium-oxide, for example withmaterial 33 being Pr_(0.7)Ca_(0.3)MnO₃ and material 92 being ayttrium-zirconium-oxide. A conductive layer 94 has been deposited overmaterial 92 to line a remaining portion of openings 86. An examplematerial 94 comprises, consists essentially of, or consists of platinum.Remaining volume of openings 86 have been subsequently filled with asacrificial material 96, for example silicon dioxide.

Referring to FIG. 27, sacrificial material 96 has been removed back toexpose conductive material 94.

Referring to FIG. 28, conductive material 94 has been removed back toexpose material 92, and material 92 has then been removed from outwardlyof filled openings 86 thereby exposing materials 58 and 82.

Referring to FIG. 29, sacrificial material 96 (not shown) has beenremoved by etching from being received within openings 86, and anotherconductive material 98 substituted therefore. An example conductivematerial is TiN, and which has subsequently been planarized back atleast to the outer surfaces of materials 58 and 82 in FIG. 29. Thereby,local vertical bit line extensions 30 comprising conductive material 98and conductive material 94 have been formed.

FIG. 30 depicts subsequent removal of materials 82 and 72 (not shown).FIG. 31 depicts subsequent fill with insulative material 83 which may beof the same or different composition from that of material 58.

FIG. 32 depicts subsequent processing, by way of example only, wherebybit lines 26 have been fabricated which include a plurality ofhorizontally oriented global bit lines 28 in electrical connection withlocal vertical bit line extensions 30 which extend through multiple ofthe tiers of memory cells. Global horizontal bit lines 28 are shown asbroken for clarity in the figure.

The embodiment described above in connection with FIG. 32 is but oneexample of an array of vertically stacked tiers of non-volatile crosspoint memory cells. Such comprises a plurality of horizontally orientedword lines within individual tiers of memory cells. Such alsoencompasses a plurality of horizontally oriented global bit lines havinglocal vertical bit line extensions extending through multiple of thetiers of memory cells. Individual of the memory cells comprisemulti-resistive state material received between one of the horizontalword lines and one of the local vertical bit line extensions where suchcross. The multi-resistive state material comprises a composite of twodifferent composition materials. One of the two materials of thecomposite comprises a plurality of spaced blocks 90 received alongindividual of the local vertical bit line extensions, with individual ofthe blocks being associated with individual of the memory cells. Theother material 92 of the composite is of C-shape in a horizontal crosssection and extends continuously along individual of the local verticalbit line extensions through multiple of the tiers.

An alternate example embodiment of an array construction 54 e, and of amethod of forming an array, is next described with respect to FIGS.33-36. Like numerals from the FIGS. 10-32 embodiments have been utilizedwhere appropriate, with differences being indicated with the suffix “e”or with different numerals. Array construction 54 e is the same as thatof construction 54 in FIG. 23, but shown at a different cross-sectionalcut and without showing the partial construction shown at the far rightin FIG. 23. In FIG. 33, the depicted front x-axis cut is along the frontedge of an opening 86, the y-axis cut is along a left edge of an opening86, and spaced sacrificial blocks 78 are thereby viewable in thedepicted front face of construction 54 e. Accordingly, spacedsacrificial blocks 78 are encapsulated by insulative material 80 and 58,but for openings 86 which have been etched to expose spaced sacrificialblocks 78.

Referring to FIG. 34, exposed spaced sacrificial blocks 78 (not shown)have been etched selectively relative to insulative materials 80 and 58,thereby leaving void spaces 88 there-behind. Accordingly, substratefragment 54 e in FIG. 34 is of the same construction as that of FIG. 24,but only showing a portion thereof at the different above-identified xand y cuts.

Referring to FIG. 35, void spaces 88 have been lined withmulti-resistive state material 33 e. Such may be homogenous ornon-homogenous, and comprise any of the classifications and specificmaterials identified above, by way of examples. In one embodiment and asshown, multi-resistive state material 33 e which lines void spaces 88 isformed to be continuous between the depicted tiers.

Referring to FIG. 36, conductive material 94 e has been deposited withinlined void spaces 88 and planarized back, thereby forming what will bevertical bit line extensions 30 e which extend through multiple tiers ofthe memory cells. Individual of local vertical bit line extensions 30 ecomprise portions which are received laterally adjacent lined voidspaces 88, now filled with material 94 e, received within multiple ofthe tiers. In one embodiment and as shown in FIG. 36, conductivematerial 94 e has been deposited or formed to be homogenous andcontinuous within the openings within which the local vertical bit lineextensions 30 e are formed. Alternately, by way of example, the localvertical bit line extensions might be formed by etching of the depositedconductive material followed by deposition of a conductor material ofdifferent composition from that of the conductive material. Such isshown by way of example only in FIG. 37 with respect to anarray/substrate fragment 54 f. Like numerals from the above-describedembodiments have been utilized where appropriate, with differences beingindicated with the suffix “f” or with different numerals. In FIG. 37,conductive material 94 f has been etched, and in one embodiment has beenetched in a substantially anisotropic manner as shown. A conductormaterial 95 of different composition from that of 94 f has beendeposited, and materials 94 f and 95 then planarized back, therebyforming local vertical bit line extensions 30 f.

A plurality of horizontally oriented global bit lines would subsequentlybe formed in electrical connection with local vertical bit lineextensions 30 e/30 f. FIG. 38 depicts such an example with respect tosubstrate fragment 54 f in the formation of bit lines 26 f havinghorizontally oriented global bit lines 28 having local vertical bit lineextensions 30 f. Hard-masking material 82 (not shown) may be replacedwith another material, for example an insulative oxide material 99 asshown.

An embodiment of the invention encompasses an array of verticallystacked tiers of non-volatile cross point memory cells. Such an arraycomprises a plurality of horizontally oriented word lines withinindividual tiers of memory cells. A plurality of horizontally orientedglobal bit lines are provided which have local vertical bit lineextensions extending through multiple of the tiers of memory cells.Individual of the memory cells comprise multi-resistive state materialreceived between one of the horizontal word lines and one of the localvertical bit line extensions where such cross. Such crossing horizontalword lines and local vertical bit line extensions comprise opposingconductive electrodes of individual memory cells where such cross, witha multi-resistive state material comprising a C-shape in a verticalcross section. For example, either of the embodiments of FIGS. 36 and 37when incorporating horizontally oriented global bit lines showmulti-resistive state material 33 e as comprising a C-shape in avertical cross section taken through former void spaces 88.

In one embodiment, the multi-resistive state material extendscontinuously along individual of the local vertical bit line extensionsthrough multiple of the tiers. In one embodiment, the multi-resistivestate material comprises a C-shape in a horizontal cross section. Forexample, either of the embodiments of FIGS. 36 and 37 havemulti-resistive state material 33 e in a C-shape in a horizontal crosssection taken through former individual void spaces 88.

In one embodiment, the local vertical bit line extensions laterally fillcenter volume of the C-shape. In one embodiment, the local vertical bitline extensions are individually homogenous, for example as shown in theembodiment of FIG. 36. In one embodiment, the individual horizontallyoriented global bit lines and local vertical bit line extensions are nothomogenous, for example as shown in the embodiment of FIGS. 37 and 38.

An alternate embodiment array construction 54 g is next described withreference to FIGS. 39-45. Like numerals from the FIGS. 10-38 embodimentshave been utilized where appropriate, with differences being indicatedwith the suffix “g” or with different numerals.

Referring to FIG. 39, array construction 54 g comprises conductivematerial 165 received between insulative material 58 at tiers 16, 18, 20and 22. Tier 16 may or may not be a dummy tier in this embodiment.Conductive material 165 may or may not be homogenous, with an examplebeing titanium nitride. Such is shown as having been patterned to form astair step-like construction for providing horizontal area for lateretching electrical contacts (not shown) to conductive material 165.Stair-stepping may also be used with any of the above-describedembodiments. Regardless, an insulative material 170 and an adjacenthardmask 172 have been formed. Material 170 may be the same as ordifferent from the composition of material 58. An example material 172is silicon nitride.

Referring to FIG. 40, horizontally elongated trenches 174 have beenetched as shown. Thereby, a plurality of horizontally oriented wordlines 176 have been formed within individual tiers 16, 18, 20 and 22.

Referring to FIG. 41, trenches 174 have been filled with insulativematerial 178 followed by planarizing such back, for example by chemicalmechanical polishing, to stop on hardmask material 172. Material 178 maybe the same as or different from the composition of materials 170 and/or58.

Referring to FIG. 42, a patterned hardmask 180 has been formed as shown.An example material 180 is silicon nitride. Regardless, material 180 maybe the same or different as underlying hardmask material 172.

Subsequent processing is described wherein horizontally oriented globalbit lines will be formed using a trench and refill technique.Alternately by way of example only, such may be formed by deposition andsubtractive etch techniques. Referring to FIG. 43, a material 182 hasbeen deposited, and within which trenches will be subsequently formedand filled. An example material 182 is silicon dioxide.

Referring to FIG. 44, a suitable mask (not shown) has been used to formmask openings (not shown) of an outline corresponding to trenches 184.Such mask openings run orthogonal to the openings within hardmask 180.Accordingly, subsequent etching of materials 182, 178, and 58 formstrenches 184 in material 182 and openings 186 extending downwardlythere-from within materials 8 and 178 between every other immediatelyadjacent pairs of horizontally oriented word lines 176.

Referring to FIG. 45, multi-resistive state material 190 has beendeposited to line trenches 184 and openings 186. Such may or may not behomogenous, with any of the multi-resistive state materials as describedabove being examples. Thereafter, conductive material 192 has beendeposited to overfill remaining volume of trenches 184 and openings 186.Subsequently, materials 190 and 192 have been planarized back to atleast the elevationally outermost surfaces of material 182. Such formsbit lines 194 which comprise a plurality of horizontally oriented globalbit lines 196 having local vertical bit line extensions 198 extendingtherefrom through multiple of the tiers of memory cells, with individualof such memory cells being depicted with phantom circles 200.

FIG. 46 illustrates an embodiment of a computer system 400. Computersystem 400 includes a monitor 401 or other communication output device,a keyboard 402 or other communication input device, and a motherboard404. Motherboard 404 may carry a microprocessor 406 or other dataprocessing unit, and at least one memory device 408. Memory device 408may comprise an array of memory cells, and such array may be coupledwith addressing circuitry for accessing individual memory cells in thearray. Further, the memory cell array may be coupled to a read circuitfor reading data from the memory cells. The addressing and readcircuitry may be utilized for conveying information between memorydevice 408 and processor 406. Such is illustrated in the block diagramof the motherboard 404 shown in FIG. 47. In such block diagram, theaddressing circuitry is illustrated as 410 and the read circuitry isillustrated as 412.

Processor device 406 may correspond to a processor module, andassociated memory utilized with the module may comprise variousstructures of the types described with reference to FIGS. 1-45.

Memory device 408 may correspond to a memory module, and may comprisevarious structures of the types described with reference to FIGS. 1-45.

FIG. 48 illustrates a simplified block diagram of a high-levelorganization of an electronic system 700. System 700 may correspond to,for example, a computer system, a process control system, or any othersystem that employs a processor and associated memory. Electronic system700 has functional elements, including a processor 702, a control unit704, a memory device unit 706 and an input/output (I/O) device 708 (itis to be understood that the system may have a plurality of processors,control units, memory device units and/or I/O devices in variousembodiments). Generally, electronic system 700 will have a native set ofinstructions that specify operations to be performed on data by theprocessor 702 and other interactions between the processor 702, thememory device unit 706 and the I/O device 708. The control unit 704coordinates all operations of the processor 702, the memory device 706and the I/O device 708 by continuously cycling through a set ofoperations that cause instructions to be fetched from the memory device706 and executed. The memory device 706 may include various structuresof the types described with reference to FIGS. 1-45.

FIG. 49 is a simplified block diagram of an electronic system 800. Thesystem 800 includes a memory device 802 that has an array of memorycells 804, address decoder 806, row access circuitry 808, column accesscircuitry 810, read/write control circuitry 812 for controllingoperations, and input/output circuitry 814. The memory device 802further includes power circuitry 816, and sensors 820, such as currentsensors for determining whether a memory cell is in a low-thresholdconducting state or in a high-threshold non-conducting state. Theillustrated power circuitry 816 includes power supply circuitry 880,circuitry 882 for providing a reference voltage, circuitry 884 forproviding a first interconnection line (for instance, a word line) withpulses, circuitry 886 for providing a second interconnection line (forinstance, another word line) with pulses, and circuitry 888 forproviding a third interconnection line (for instance, a bit line) withpulses. The system 800 also includes a processor 822, or memorycontroller for memory accessing.

The memory device 802 receives control signals from the processor 822over wiring or metallization lines. The memory device 802 is used tostore data which is accessed via I/O lines. At least one of theprocessor 822 or memory device 802 may include various structures of thetypes described with reference to FIGS. 1-45.

The various electronic systems may be fabricated in single-packageprocessing units, or even on a single semiconductor chip, in order toreduce the communication time between the processor and the memorydevice(s).

The electronic systems may be used in memory modules, device drivers,power modules, communication modems, processor modules, andapplication-specific modules, and may include multilayer, multichipmodules.

The electronic systems may be any of a broad range of systems, such asclocks, televisions, cell phones, personal computers, automobiles,industrial control systems, aircraft, etc

In compliance with the statute, the subject matter disclosed herein hasbeen described in language more or less specific as to structural andmethodical features. It is to be understood, however, that the claimsare not limited to the specific features shown and described, since themeans herein disclosed comprise example embodiments. The claims are thusto be afforded full scope as literally worded, and to be appropriatelyinterpreted in accordance with the doctrine of equivalents.

The invention claimed is:
 1. An array of vertically stacked tiers ofnon-volatile cross point memory cells, comprising: a plurality ofhorizontally oriented word lines within individual tiers of memorycells; a plurality of horizontally oriented global bit lines havinglocal vertical bit line extensions extending through multiple of thetiers of memory cells; and individual of the memory cells comprisingmulti-resistive state material received between one of the horizontallyoriented word lines and one of the local vertical bit line extensionswhere such cross, with such ones of the horizontally oriented word linesand local vertical bit line extensions comprising opposing conductiveelectrodes of individual memory cells where such cross, the horizontallyoriented word lines at least where such cross being of a conductivelyfilled C-shape in a vertical cross section with an outline of theC-shape comprising one conductive material with a central portion of theC-shape being filled with another conductive material of differentcomposition from the one conductive material.
 2. The array of claim 1wherein the one and another conductive materials are homogenous,respectively.
 3. The array of claim 1 wherein the one conductivematerial comprises platinum.
 4. The array of claim 1 wherein the oneconductive material is of higher conductivity than the anotherconductive material.
 5. The array of claim 1 wherein the anotherconductive material extends laterally outward of the C-shape outline ofthe one conductive material.
 6. The array of claim 1 wherein the one andanother conductive materials are non-homogenous, respectively.
 7. Thearray of claim 1 wherein at least one of the one and another conductivematerials is homogenous.
 8. The array of claim 1 wherein at least one ofthe one and another conductive materials is non-homogenous.
 9. The arrayof claim 1 wherein the multi-resistive state material comprises aC-shape in a horizontal cross section.
 10. An array of verticallystacked tiers of non-volatile cross point memory cells, comprising: aplurality of horizontally oriented word lines within individual tiers ofmemory cells; a plurality of horizontally oriented global bit lineshaving local vertical bit line extensions extending through multiple ofthe tiers of memory cells; and individual of the memory cells comprisingmulti-resistive state material received between one of the horizontalword lines and one of the local vertical bit line extensions where suchcross, with such ones of the horizontal word lines and local verticalbit line extensions comprising opposing conductive electrodes ofindividual memory cells where such cross, the multi-resistive statematerial comprising a C-shape in a vertical cross section.
 11. The arrayof claim 10 wherein the multi-resistive state material extendscontinuously along individual of the local vertical bit line extensionsthrough multiple of the tiers.
 12. The array of claim 10 wherein themulti-resistive state material comprises a C-shape in a horizontal crosssection.
 13. The array of claim 10 wherein the local vertical bit lineextensions laterally fill center volume the C-shape.
 14. The array ofclaim 10 wherein the local vertical bit line extensions are individuallyhomogenous.
 15. The array of claim 10 wherein the individual horizontalglobal bit lines with the local vertical bit line extensions arehomogenous.
 16. The array of claim 10 wherein, the multi-resistive statematerial extends continuously along individual of the local vertical bitline extensions through multiple of the tiers; the multi-resistive statematerial comprises a C-shape in a horizontal cross section; and thelocal vertical bit line extensions laterally fill center volume theC-shapes.
 17. An array of vertically stacked tiers of non-volatile crosspoint memory cells, comprising: a plurality of horizontally orientedword lines within individual tiers of memory cells; a plurality ofhorizontally oriented global bit lines having local vertical bit lineextensions extending through multiple of the tiers of memory cells; andindividual of the memory cells comprising multi-resistive state materialreceived between one of the horizontal word lines and one of the localvertical bit line extensions where such cross, with such ones of thehorizontal word lines and local vertical bit line extensions comprisingopposing conductive electrodes of individual memory cells where suchcross, the multi-resistive state material comprising a composite of twodifferent composition materials, one of the two materials of thecomposite comprising a plurality of spaced blocks received alongindividual of the local vertical bit line extensions with individual ofthe spaced blocks being associated with individual of the memory cells,the other of the two materials of the composite being of C-shape in ahorizontal cross section and extending continuously along individual ofthe local vertical bit line extensions through multiple of the tiers.